Two-fuel carburetor



Dec. 9, 1952 J. T. w. MOSELEY TWO-FUEL CARBURETOR 2 SHEETS-SHEET 1 Filed Jan. 31., 1948 FlGll.

IN V EN TOR.

Y E L E S O T S E M A J ATTORNEY Dec. 9, 1952 J. r. w. MOSELEY TWO-FUEL- CARBURETOR 2 SHEETS-SHEET 2 Filed Jan. 31, 1948 INVENTOR. 4 J U JAMES T; w. MOSEL'EY ATTORNEY Patented Dec. 9, 1952 TWO-FUEL CARBURETOR James T. W. Moseley, Clayton, Mo assignor'ito Carter Carburetor Corporation, St.;lLouis, Mo., .a corporation of Delaware Application January 31, 1948, Serial No. 5,538

' 2 Claims. (01.2.61-48) This invention relates to carburetors for internal combustion engines, particularly of the automotive type. It consists of a, novel construction of the fuel storage and'supplrmeans'for equipping the carburetor .tohandle'a plurality of-fuels.

ed to-supply a low test fuel under part throttle or economy conditions and a high'test'or antidetonating fuel when greater'poweris demanded.

Another object is to providea single metering arrangement which is adapted 'to control the supply of both fuels according to whichever is required at the moment.

These objects and other' more detailed objects hereafter *appearing are attained by the'device illustrated in the accompanying drawings in which Fig. 1 is a top view of a carburetor embodying the invention.

Fig. 2 isa vertical transverse section taken ub- :stantially on line 2 2 of Fig. 1.

Fig. 3 is a vertical sectiontaken substantially on line-3-3 or Fig; 2.

Fig. 4" is a section similar to"Fig.' 3, but. showing the valvesreversed.

Thec'arburetor shown includes a "downdraft induction "or'mixture conduit including the air horn portion 10, mixing chamber ll including Venturitubes l2, and outlet portion l3..having afian'gel lfor attachment to the usual engine intakemanifold. The entire mixture conduit and manifold are termed the induction system of the engine. Located at one side of the mixture conduit is a i uel bowl structure l5 having a central vertical partition 16 forminga pair of fuel chambers I? and I8. The'chambers have fuel inlet bosses l9 and 29 and the fuel level therein is controlled by well-known constant level mechanisms including a float, as at 2|, in each chamber, and a needle valve in the fuel inlet thereto.

Located near the bottoms of the-chambers are metering orifice elements Maud 25 mounted on an enlargement 26 projecting from the. floor of the bowl structure and drilled'out'i to formvertical passages 27 and 2s-directlysreceiving the orifice elements and connecting cross passage 29.

A-passage 3ll-extends at right -angles 'fromcmss passage 29 to a vertical well'3l which receives an idlingtube 32. A main nozzle passage- 33 extends from theupper portion of :well 3l into smaller venturi l2. The idling tube-at its upper end connects witha cross passage 34 and-awartical passage, shown in part; at 35, which'terminates in idling ports 8 adjacent and'posterior-t0 the edge of throttle valve lwhen closed.

Orifice elements 24 and are controlled, respectively, by meterin pins 38 and 31 having graduated lower portions projecting-throughthe orifice elements and extending upwardly through bowl cover 35. An L-shaped link or 'rod'39has a top plate element 40 with'lateral forked portions 4| and 42 which, respectively,- embrace pins 36 and 31. Pin-36 has spaced collars Hand 44 on its upper portion between the lower of which 'and forked portion'l there is compressed a coiled spring 45. Pin 3'l-has-space'd collars and between the upper of whichand'forked-portion 42 is compresseda coiled spring 48.

L-shaped .rod 39 at its lower extremity is-secured to a piston 5i] which'works in a-cylinder 5| formed in a suitable enlargement in bowl web 16. The cylinder is connected at its lower extremity by means of a passage 52 to--=a port 53 opening into the carburetor induction conduit posterior to the throttle valve so as to expose the cylinder and 'piston'to-engine intake-manifold' suction. A coiled spring 54 normally urges piston upwardly and in opposition to the force of suction on the piston.

Metering pints has a conical cut-ofi portion 55 aboveorifice element 24 and adapted to seat thereon to close the orifice element when pinj3fi is urged downwardly. .Pin 31 .hasa conicalcutoff portion "56,iocated below orifice element 25 and adapted to seat thereonwhen pin 37 is urged upwardly. Thepins are arranged with respect to the orifice elements so. that oneorttheother of the valve enlargements is seated at all timesexceptv shortly, before and after. the. transfer point.

'A. countersh'aft 5! is pivotally carried by posts 58 on top of bowl cover.38 and .has-an..arm...5.9 rigidly secured thereto. .This arm has bifurcations 60 extending on oppositesidesof. L-shaped rod 39 and beneath upper element 40 thereof. .A second arm 6| rigid wtih shaftlil is. conneotedby a link 62 to a crank 63 rigid withthethrottle shaft. The arrangementis such that the linkage and lever 59 forma one-wayoperative connection between the throttle and the metering pins.

Mounted on they left side of the bowl structure (Figs. 3 and 4) is a cap element tfiwhich secures a diaphragm 67 in position upon aboss 6.8. The space within boss 68 at the right ofthe diaphragm is connected byashort passage 69,..to.a vertical chamber .70 which opens at its .lower extremity past an inlet checkll and a screen 12 into fuel chamber IT. The upper portion of chamber 70 communicates past an outlet check 73 with a nozzle 14 discharging into the mixture conduit. A coiled spring 15 is compressed between cap structure 66 and the diaphragm and constantly urges the same towards the right or in the discharge direction. A suction passage 16 connects the space in cap element 66 and to the left of the diaphragm with a port 11 opening into the mixture conduit posterior to the throttle.

In operation, chambers l7 and [B will be connected, respectively, with sources of relatively high test or anti-detonating fuel and low test fuel. The rest positions of the metering pins and their operating mechanism is illustrated in Figs. 2 and 3. Piston 50 and, consequently, both metering pins, are urged upwardly by spring 54 so that valve enlargement 56 is seated against orifice element so as to cut off chamber l8 from the mixture conduit. At the same time, enlargement 55 on pin 36 is clear of orifice element 24.

Accordingly, during starting, high test fuel will be supplied from chamber l1. However, when the engine starts to run and is operating at idle or part throttle with high load, suction draws piston 50 and the metering pins downwardly, seating enlargement 55 on its orifice element and withdrawing enlargement 56 from element 25. Thus, fuel under this condition, when detonation does not occur, is supplied from low test chamber l8. Normally, idling fuel will be supplied from low test chamber I 8 because of normal high suction existing in the engine manifold during idling. Preferably, piston 50 will remain in its uppermost position until a suction of approximately 8 inches of mercury is exceeded in the intake manifold.

- The one-way throttle connection by means of link 62 and levers 53 and BI is adjusted so that during opening movement of the throttle, forked lever 59 moves clockwise. Under part throttle conditions, L-shaped link or rod 39 will be held downwardly against bifurcated arm 59 and, thus, the metering pins will move with the throttle. However, because of the reversed, yielding connections between the pins and suction actuated element 40, only one pin at a time will move with the throttle or the suction element. Thus, while enlargement 56 is seated (Fig. 3) metering pin 36 is free to operate to bring different portions of its tapered lower extremity into op-,

erative relationship with metering orifice 24, until element 40 drops far enough to engage collar 48 on pin 37. Thereafter, upon increase in suction, only pin 37 will move, pin being held stationary by seating of its enlargement 55 on.

orifice element 24. Thus, for slow throttle movement, the fuel from-whichever chamber is connected to the mixture conduit at the moment will be metered in proportion to the degree of throttle opening. Both metering pins have relatively small metering portions adjacent their lower extremities to provide for maximum effective size of the corresponding metering orifice when this portion is located therein.

In order to prevent both cut-off enlargements 55 and 56 being seated at the same time, the lost motion provided on pin 3'. in the position of Fig. 3 and on pin 36 in the position of Fig. 4 is such that this lost motion will be exhausted just before the cut-oif enlargement of the other pin seats. Thus, there will be a short period when fuel will be supplied through both metering orifices. However, in practice, this condition will scarcely ever exist so that, in effect, the fuels in the separate fuel chambers will be supplied alternatively. The use of the fuel in the high test chamber as the pick up charge injected by the accelerating pump is desirable since the accelerating conditions are accompanied normally by a drop of suction in the engine manifold and a tendency to detonate.

The arrangement, accordingly, insures a supply of anti-detonating fuel at times when detonation is likely to occur. At other times, the less expensive low test fuel is supplied.

The invention may be modified in various respects as will occur to those skilled in the art and the exclusive use of all modifications as come within the scope of the appended claims is contemplated.

Iclaim:

1. In a carburetor, a mixture conduit having a throttle, separate fluid chambers for independent supply of highand low-test fuels, supply passages between said conduit and said chambers, and means for controlling the flow of fuel through said passages comprising combined metering and fuel cut-oil members for the individual chambers in said passages, an actuator responsive to changes in manifold pressure for positioning said members, and a mechanical connection between said actuator and said throttle, including separate, successively acting means for each member connected to the individual members for sequential operation of the members during opening movement of the throttle, said connection positioned in the path of movement of said actuator so as to limit movement of said actuator when the throttle is partly open.

2. In a carburetor, a mixture conduit having a a throttle, separate fluid chambers for independent supply of highand low-test fuels, supply passages between said conduit and said chambers and means for controlling the flow of fuel through said passages comprising metering orifices for each said passage, control valves for said orifices disposed in parallel relation and extending therethrough, an orifice closing portion on each valve, one on the upstream side of one orifice and the other on the downstream side of the other orifice, a differential pressure operated valve actuator, yielding connections between said actuator and said valves positioned in opposed relation relative to said actuator, and having a one-way operating connection with each of said valves, respectively, to permit continued relative movement between one of said valves and said actuator when either valve is seated, and a mechanical connection between said throttle and actuator including a means to position the actuator and acting to restrict its range of movement.

JAMES T. W. M'OSELEY.

REFERENCES CITED The following references are of record in the file of this patent: 

